This invention relates to solar heating and evaporation plants and, more particularly, to such plant comprised of a plurality of relatively small solar stills or heaters.
The art of producing drinking water from salt water by means of solar distillation is well known, particularly in arid, coastal regions. Many designs of solar stills are known which use conventional materials such as wood, metal, concrete, plastic, glass, etc. Typically, a material transparent to solar radiation is supported over a pool of salt or brackish water in such a manner as to allow the radiant energy to heat and vaporize the water. The vapor thus produced then condenses and the condensate coalesces into a body of distilled potable water.
Since the solar energy used to provide the heat of vaporization of the impure water is free, the economy and productivity of a solar still is tied primarily to the cost of construction and material.
As examples of prior solar heating systems, there may be mentioned U.S. Pat. No. 2,213,894, issued Sep. 3, 1940, which shows a solar water heater having a transparent dome-shaped top. This is used to heat a coil mounted within the dome.
U.S. Pat. No. 5,468,351, issued Nov. 21, 1995, shows a system with a tapered glass or plastic roof mounted over a liquid reservoir and associated with a liquid recovery member. The transparent roof has on its inner surface a saponified cellulose-based film.
Another solar evaporator is described in U.S. Pat. No. 3,282,327, issued Nov. 1, 1966, having an inclined glass roof and collection troughs for potable water. The surface of the impure water has particles of plastic material floating on the surface which serve to increase the evaporation rate of the water being heated by solar radiant energy.
Yet another solar distillation system is shown in U.S. Pat. No. 3,801,474, issued Apr. 2, 1974. This includes a rectangular container for salt water and a transparent plastic inclined roof portion sitting over the body of salt water. Potable water is collected in troughs around the perimeter of the roof section. Cellular glass nodules float on the surface of the salt water to enhance the evaporation efficiency.
It is the object of the present invention to provide further improvements to the general efficiency of solar heating and evaporation systems.